Behaviour of setjmp/longjmp and reg

mcdonald at uxe.cso.uiuc.edu mcdonald at uxe.cso.uiuc.edu
Thu Feb 9 00:04:00 AEST 1989


>>>> The subject being escape sequences from terminals and their
problems >>>>>>>>

The problem comes from trying to push a large round plug in a small
square hole. The keyboard I am typing this on has 101 keys (one of
which is indeed labeled 'esc'.) Lets see, 101x2 = 202 . 202 < 256.
This implies that the keyboard could send a separate key code for
when a key is pushed down, and when it is let up, and still have
room left over for an EOF indicator. In fact, it does just that. 
No multicharacter sequences are necessary. The computer it is attached to
makes good use of having the complete state of the keyboard at hand.
I seriously doubt that anyone can type fast enough to overload
even a 1200 baud line. My mother can't; for many years she was the fastest
typest in Texas. Of course, I suppose somebody could sit on it :-).
The character-code only terminal isn't yet obsolete, it is just slowly
being pushed out of the way by the more complete model.



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